The Physical Properties of the melanins are to be investigated in order to shed more light on the origin of their amorphous semiconductor nature. Time Domaine reflectometry has been employed to investigate melanin-water interactions. These Studies have demonstrated dielectric constants in the 60-90 range under appropriate conditions, a value far higher than that predicted from the additive components which would predict a value of 25. The presence of salts was also found to increase the dielectric constant, yielding the conclusion that the anomalously high dielectric constant arose from melanin-water-ion interactions. These studies have continued into the investigation of the cytoprotective-cytotoxic nature of the melanosome and relate to the anomalously high absorption of sound waves in melanins. These theoretical and experimental data have been applied to the development of treatments for human tumors, in particular human malignant melanomas, using continuous wave ultrasound in the 1-3 MHz range. Data from the first twenty human tumors treated, half of which were melanomas, show a 50% overall objective response rate. While most of the therapeutic efficacy in unpigmented tumors must be attributed to thermal effects, some melanomas with very high pigment content show a striking response which is difficult to attribute solely to thermal effects.